Paper machine headbox



June 12, 1962 K. c. LOGAN ET AL 3,038,538 PAPER MACHINE HEADBOX Filed May 28, 1958 kma/i MW 1% ATTORNEY United States Patent Office 3,038,538 Patented June 12, 1962 3,038,538 PAPER MACHINE HEADBOX Kenneth C. Logan, 137 Rue Pasteur, Sillery, and James Mardon, 472 Ave. Jean Dequen, Ste. Foy, both of Quebec City, Quebec, Canada Filed May 28, 1958, Ser. No. 738,365 Claims. (Cl. 162336) This application relates to paper machine headboxes and is a continuationin-part of copending application, Serial No. 537,531, filed September 29, 1955, now Patent No. 2,892,499.

The desirable achievement of a stabilized and equalized flow of pulp stock from the slice of a paper machine onto the wire has in the past been diificult to attain under all circumstances of operation and has resulted in problems which have not been satisfactorily solved.

A general object of the present invention is to provide a headbox having a slice incorporated therein and which results in the production of an even stabilized flow of stock onto the wire across the width of the machine.

The invention contemplates the provision of a paper machine headbox having converging walls terminating in slice lips, said convering walls extending across the width of the paper machine and having substantial length thereby to provide a stabilizing and equalizing effect on paper stock flow therebetween in a direction perpendicular to the convergence of the walls. The provision of a restricted slot or opening leading from a stock inlet section to the main section of the headbox provides a rectification of flow to the machine direction from the initial feed area of the headbox.

The invention will be described with reference to the accompanying drawing, in which FIGURE 1 is a sectional side elevation of a headbox in accordance with the invention,

FIGURE 2 is a partial sectional side elevation of a modified form of headbox,

FIGURE 3 is a partial sectional end elevation of the headbox shown in FIGURE 2, taken in a plane identified by line 3-3, FIG. 2,

FIGURE 4 is a partial sectional side elevation of a further modified form of headbox including feeding means, taken in a plane identified by line 4-4, FIG. 5,

FIGURE 5 is a partial sectional plan view of the headbox shown in FIGURE 4, and

FIGURE 6 is a partial sectional side elevation of a headbox showing slot adjustment means.

Referring to FIGURE 1, 1 is a headbox having a cross flow inlet portion 2, a nozzle portion 3, and an intermediate expansion portion 4. The inlet portion 2 communicates with portion 4 through a slot 5 extending across the width of the box and which may be formed by converging walls 6 inclined at a relaitvely steep angle and contiguous converging walls 7 inclined at a less steep angle. The walls 8 of portion 4 diverge at a gradual angle preferably in the range of 5 to from the slot 5. The walls 9 of portion 3 converge to form the slice lips 10. A breast roll is indicated at 11 and a forming wire at 12.

The stock is fed into one end of inlet portion 2, for distribution through slot 5, the converging walls of which provide constant velocity across the face of the slot. Overflow stock discharges from the other end of portion 2. Thus, a first stage rectification of flow to the desired machine direction is accomplished by the converging approach to the slot 5. It will be apparent that varying forms of converging walls may be employed to constitute the approach to slot 5. A second stage rectification is accomplished by the gradual expansion of portion 4 from slot 5. If desired, means such as perforated rolls 13 may be provided in portion 4 to prevent separation. A final or third stage rectification is accomplished by the convergence of the walls 9 forming nozzle portion 3.

It will be apparent that use of an inlet portion having a flow distributing slot, such as illustrated in FIGURE 1, may be employed with various types of headboxes.

FIGURES 2 and 3 illustrate a modified form of inlet portion 14, similar to inlet portion 2, and having converging walls 15 terminating in slot 16. Rectification of the stock flow by converging walls 15 may be aided by means of a perforated roll 17 located between such walls. A further means of aiding such rectification, more particularly for use with deaerated stock, is the provision of fins or discs 13 on an axial shaft 19 within roll 17.

It will be apparent that oscillation of shaft 19 and discs 18, which extend perpendicularly to the axis of the roll, will impart a rectifying effect upon the stock flow.

It will be apparent that either of the roll 17 or the finned shaft 19 may be employed without the other. FIGURE 4 illustrates use of the roll 17 only.

Various means may be employed for feeding stock to the inlet section 14 (or to the inlet section 2). One suitable means is illustrated in FIGURES 4 and 5 wherein a perforated plate 20 defines an end wall of section 14 and a transversely inclined outer wall 21 provides a tapered feed chamber 22 with a stock inlet 23 at the wide end of the chamber and an outlet 24 for overflow stock at the narrow end of the chamber. Thus a substantially even flow of stock is provided through the perforated plate 241 into the inlet section across the width of the machine.

The slot 5 (or the slot 16) may be of non-uniform or adjustable width. One manner of accomplishing this is illustrated in FIGURES 6, wherein a portion of top wall 7 and a portion of top wall 8 adjacent the slot are removed and replaced by a flexible strip 25 formed of stainless steel or other suitable material. One edge of strip 25 is fixed to wall 8 and the opposite edge has sliding engagement with the inner surface of wall 7. Means for moving strip 25 in a vertical direction may include a plurality of rods 26, one end of each of which is fixed to the midportion of strip 25 and the other end of which is supported in a frame member 27. Each rod is movable in an up and down direction and is locked in any adjusted position by means of nuts 28. The slidable edge portion of strip 25 may be clamped in any adjusted position by means of a strap 29 and bolts 30.

We claim:

1. In a headbox for a paper machine having a breast roll rotatable on a horizontal axis and a forming wire belt passing over and about said roll to define planar pass extending forwardly therefrom and transversely horizontal, said headbox having a general plane of symmetry substantially coincident with the plane of said pass, said headbox also being of uniform cross section in planes normal to said axis and extending throughout the width of said belt, said headbox comprising a cross fiow inlet portion having upper and lower planar walls, said walls sloping inwardly and forwardly toward and upon opposite sides of said plane of symmetry to define a first slot; thence diverging forwardly and outwardly from said first slot upon respective opposite sides of said plane, thence converging forwardly and inwardly toward said plane to terminate in contiguous, vertically-spaced slice lips extending transversely across and over said belt adjacent said roll.

2. A headbox as in claim 1, said first slot being adjustable in effective width transversely of the direction of fiow of material therethrough and normal to said axis.

3. In a headbox for a paper-making machine having a breast roll rotatable on a horizontal axis and a forming wire belt passing over and about said roll to define a horizontal upper planar pass extending forwardly therefrom, said headbox having a plane of symmetry substantially coincidental with said planar pass, and a uniform cross section in planes normal to said axis, said headbox comprising a cross flowdnlet portion having upper and lower fiat walls on opposite sides of said plane of symmetry, said walls having first portions converging forwardly and inwardly at equal acute angles with said plane to conjointly define between them a first slot, parallel with said axis, second portions diverging forwardly and outwardly from said first slot upon opposite sides of said plane and at equal acute angles with respect thereto, and third portions converging forwardly and inwardly at equal acute angles with said plane from the forward edges of said second portions, respectively, to terminate in edges defining a second slot over said pass and parallel with said axis.

4. A headbox as in claim 3, and a vertically disposed foraminous wall in said cross flow inlet portion and extending between said upper and lower walis at the rearward edges of said first portions thereof.

5. A headbox as in claim 3, said first slot comprising a flexible sheet fixed along one edge longitudinally of a portion of a wall forming said first slot and slidably secured along the other portion of the same wall of said 4 slot, and means contacting the central portion of said sheet and operable to variably flex the same to variably adjust the effective width of said slot.

References Cited in the file of this patent UNITED STATES PATENTS 1,707,375 Upson Apr. 2, 1929 1,928,107 Lang Sept. 26, 1933 2,156,445 Baxter May 2, 1939 2,203,802 Thaler June 11, 1940 2,281,293 Lang Apr. 28, 1942 2,308,370 Kellett et al Ian. 12, 1943 2,329,799 Thorsen Sept. 21, 1943 2,344,282 Berry et a1. Mar. 14, 1944 2,894,581 Goumeniouk July 14, 1959 2,929,449 Mardon et a1 Mar. 22, 1960 FOREIGN PATENTS 668,822 Great Britain Mar. 26, 1952 842,302 Germany June 26, 1952 855,502 Germany Nov. 13, 1952 OTHER REFERENCES Mardon et al.: Pulp and Paper Magazine of Canada, October 1954; Part 11, pages 110-119. 

